Abstract

Thermodynamic calculation and phase-field simulation have been conducted to investigate the misfit strain-temperature phase diagrams,dielectric property, and domain stability of asymmetric ferroelectriccapacitors (FCs), with considering the effects of dissimilar screening properties and work function steps at the two interfaces. The distinct features of asymmetric FCs from their symmetric counterparts have been revealed and discussed. Polar states with nonzero out-of-plane polarization in parallel with the built-in field are found preferential to form in asymmetric FCs. Meanwhile, the built-in field breaks the degeneracy of states with out-of-plane polarization in anti-directions. This leads to the necessity of redefining phases according to the bistability of out-of-plane polarization. Moreover, the phase stability as well as the dielectric behavior can be significantly controlled by the properties of electrodes, misfit strain, and temperature. The phase-field simulation result also shows that polydomain instability would happen in asymmetric FCs as the equivalence of domain stability in anti-directions is destroyed.

Received 09 September 2013Accepted 20 February 2014Published online 04 March 2014

Acknowledgments:

The authors gratefully acknowledge the financial support of NSFC (Nos. 51172291 and 11232015). Y. Zheng also thanks support by the Fundamental Research Funds for the Central Universities, NCET in University, Research Fund for the Doctoral Program of Higher Education, and Fok Ying Tung Foundation, Science and Technology Innovation Project of Guangdong Provincial Education Department and Guangdong Natural Science Funds for Distinguished Young Scholar.